Dear Reader,

Men who are born with two X chromosomes [or a genotype (genetic information) of XXY instead of the more typical XY] usually develop a condition called Klinefelter's syndrome. Klinefelter's is the most common sex chromosome disorder, affecting approximately 1 in 500 males across all ethnic and racial groups.

Because the "extra" chromosome is a sex chromosome, most of the physical effects of Klinefelter's syndrome become apparent during puberty, if at all. Men with Klinefelter's tend to be tall and have decreased facial hair and muscle mass. They are also more likely to have breast development and very small testicles. Some of these physical differences are thought to be the result of decreased testosterone levels. Injections of synthetic testosterone have been found to increase muscle development and bone density, giving men with Klinefelter's syndrome a more traditionally masculine appearance. However, this replenishment of testosterone cannot correct the infertility that most with Klinefelter's have as a result of the condition. Some research suggests that early (recommended by ages 11 - 13 years) testosterone replacement therapy may decrease the incidence and severity of learning disabilities that can be related to having Klinefelter's, potentially improving overall quality of life. Research on the cognitive problems associated with Klinefelter's are still in the early stages though.

Since the symptoms of Klinefelter's syndrome can vary significantly from person to person, there is no one specific time when people with this disorder are usually identified. Plus, experts think that people with mild symptoms often escape diagnosis altogether. Among those who are diagnosed with Klinefelter's, some are identified during childhood, when their parents seek treatment for speech problems and learning and/or developmental difficulties that present at school, or at puberty, when they fail to develop secondary sex characteristics. Others are diagnosed in utero, when their mothers undergo amniocentesis or other pre-natal tests. Some men with few symptoms are not diagnosed until they seek counseling for infertility. Definitive diagnosis of Klinefelter's syndrome is made through laboratory analysis and chromosomal karyotyping (an examination of chromosomes) of a blood sample. A complete medical and neurological evaluation is also done, and, when necessary, patients are referred to a psychiatrist, psychologist, speech pathologist, and/or language therapist. With proper management of the disorder throughout life, many people with Klinefelter's syndrome lead healthy and normal lifestyles.

What is important, if you know this man or have some relationship with him, is the context in which he told you. How did this come up in conversation? And how does this affect him, or you? What sort of info and support has he gotten or does he need? If he is a good friend, perhaps you could ask him your questions, if you are willing to respect his right to respond with a, "butt out." If he's a casual acquaintance, it may be interesting information, and, as a result, you had an opportunity to learn more about the complexities and variations of genetics and life.

For more information about Klinefelter's syndrome and other sex chromosome variations, check out the American Association for Klinefelter Syndrome Information and Support, the Klinefelter Syndrome and Associates, the Klinefelter Syndrome Support Group, and the Developmental Disabilities Digest Web sites.

Alice

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